1. Field of the Invention
The invention relates to an apparatus for treating tumors such as cancer, benign prostatic hyperplasia, etc., by irradiating vital tissues with various forms of energies such as laser beams, microwaves, radio frequency, and ultrasonic waves.
2. Description of the Related Art
Various apparatuses have been known for treating lesions to reduce or eliminate them by means of heating, alteration, sphacelation, coagulation, cauterization or evaporation of the tissues of the lesions by irradiating them with energies from the emitting part encased in the distal end of a long shaft-like main unit inserted into a human body either via a body cavity or an opening produced by a small incision.
For example, in case of the treatment of benign prostatic hyperplasia, it is customary to apply a transurethral treatment since the prostate is located in the bottom of the bladder and at a position to surround the bottom of the proximal part of the urethra.
An apparatus suitable for transurethral treatments has been proposed, in which a long main unit inserted into the urethra and the emitting part is reciprocated longitudinally while changing the emitting angle of laser beams so that the laser beams can be converged on the target region, which is located deep inside the tissue. Using the particular apparatus, only the target region can be heated to a desired temperature for treatment while other regions are maintained at low temperatures
However, since said apparatus requires a complicated and sizeable constitution, as it has to have a combination of a long main unit and a drive mechanism for reciprocating the emitting part inside the main unit, the long main unit is reused after cleaning and disinfection after a use. In other words, the long main unit ends up being used against multiple patients repeating cleaning and disinfection.
Consequently, the functions and performances of the apparatus degrade as the time goes on resulting from its repetitive uses, and it may gradually become incapable of providing sufficient curative effects, and increase the burden on the patient. It is also a severe burden on the clinical staff to have to clean and disinfect the apparatus completely to eliminate the concern for contamination.
Moreover, if the positioning of the distal end of the main unit is inaccurate in laser beam irradiation, it can cause either excessively overlapping irradiation on the same region or irradiation on off-target regions, in either of which a sufficient curative effect cannot be achieved, and cause additional burdens on the patient due to a prolonged treatment period. Therefore, it is desirable to locate the distal end of the main unit precisely within the urethra based on a sufficient observation in the forward direction, which is the inserting direction of the main unit, as the long main unit is being inserted into the urethra.
However, the apparatus of the prior art is built in such a way that the reflecting part of the laser beam located in the emitting part interferes with the forward viewing field. On the other hand, if the endoscope is placed in the main unit in such a way as not to interfere with the forward viewing field, the diameter of the endoscope will become limited as there is a limit to the size of the main unit. Thus, it is difficult to install an endoscope with a sufficiently clear and wide field of view.
Moreover, since the distance between the distal end of the optical fiber from which the laser beam is emitted and the reflecting part varies with the movement of the reflecting part, it is necessary to stabilize the spot diameter of the laser beam by providing a special optical system at the distal end of the optical fiber. Moreover, in order to have a variable reflection angle, it requires a complex hinge mechanism consisting of many components.
Because of such a complex constitution, it inevitably leads to degradation of functions and performances as the time goes on resulting from repeated uses, and becomes difficult to obtain desirable and sufficient curative effects, and results in an increased burden on the patient""s part.
It is therefore a general object of the present invention to provide a medical energy irradiation apparatus that reduces the patient""s burden.
More specifically, it is an object of the invention to provide an energy irradiation apparatus for medical treatment of tissues through irradiation of energy including a long main unit, an emitting part, a power transmission member, a drive mechanism, a first engaging member, and a second engaging. The emitting part is disposed moveably inside a distal end of the main unit for emitting energy transmitted to a distal side from a proximal side. The power transmission member is disposed moveable inside the main unit. The emitting part is mounted to a distal end of the power transmission member. The drive mechanism reciprocates the power transmission member in a longitudinal direction of the main unit. The first engaging member is provided inside the power transmission member for receiving a drive force from the drive mechanism. The second engaging member is provided in the drive mechanism for engaging removably with the first engaging member.